CVE-2026-42268: CWE-191: Integer Underflow (Wrap or Wraparound) in owasp-modsecurity ModSecurity
ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. From 3.0.0 to before 3.0.15, there is an unhandled exception (std::out_of_range) caused by unsigned integer underflow in libmodsecurity3 if the user (administrator) uses a rule any of @verifySSN, @verifyCPF, or @verifySVNR. This vulnerability is fixed in 3.0.15.
AI Analysis
Technical Summary
ModSecurity, an open source web application firewall engine for Apache, IIS, and Nginx, has an integer underflow vulnerability (CWE-191) in versions from 3.0.0 up to but not including 3.0.15. The issue arises in libmodsecurity3 when certain verification rules (@verifySSN, @verifyCPF, @verifySVNR) are used by an administrator, causing an unhandled std::out_of_range exception due to unsigned integer underflow. This can lead to unexpected behavior or crashes. The vulnerability has a CVSS 4.0 score of 8.2 (high severity). It is addressed by updating to ModSecurity version 3.0.15.
Potential Impact
Exploitation of this vulnerability can cause ModSecurity to throw an unhandled exception, potentially leading to denial of service or disruption of the web application firewall functionality. There are no known exploits in the wild as of the published date. The impact is rated high due to the potential for service disruption.
Mitigation Recommendations
This vulnerability is fixed in ModSecurity version 3.0.15. Users should upgrade to version 3.0.15 or later to remediate the issue. No other official remediation or temporary fixes are indicated. Patch status is confirmed by the vendor advisory stating the fix is included in 3.0.15.
CVE-2026-42268: CWE-191: Integer Underflow (Wrap or Wraparound) in owasp-modsecurity ModSecurity
Description
ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. From 3.0.0 to before 3.0.15, there is an unhandled exception (std::out_of_range) caused by unsigned integer underflow in libmodsecurity3 if the user (administrator) uses a rule any of @verifySSN, @verifyCPF, or @verifySVNR. This vulnerability is fixed in 3.0.15.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
ModSecurity, an open source web application firewall engine for Apache, IIS, and Nginx, has an integer underflow vulnerability (CWE-191) in versions from 3.0.0 up to but not including 3.0.15. The issue arises in libmodsecurity3 when certain verification rules (@verifySSN, @verifyCPF, @verifySVNR) are used by an administrator, causing an unhandled std::out_of_range exception due to unsigned integer underflow. This can lead to unexpected behavior or crashes. The vulnerability has a CVSS 4.0 score of 8.2 (high severity). It is addressed by updating to ModSecurity version 3.0.15.
Potential Impact
Exploitation of this vulnerability can cause ModSecurity to throw an unhandled exception, potentially leading to denial of service or disruption of the web application firewall functionality. There are no known exploits in the wild as of the published date. The impact is rated high due to the potential for service disruption.
Mitigation Recommendations
This vulnerability is fixed in ModSecurity version 3.0.15. Users should upgrade to version 3.0.15 or later to remediate the issue. No other official remediation or temporary fixes are indicated. Patch status is confirmed by the vendor advisory stating the fix is included in 3.0.15.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-26T11:53:27.706Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a03a0decbff5d86101d5c7c
Added to database: 5/12/2026, 9:51:26 PM
Last enriched: 5/12/2026, 10:07:27 PM
Last updated: 5/13/2026, 4:52:19 AM
Views: 6
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
External Links
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.